When police arrived they found Noll sitting in the driver's seat of his maroon Subaru in the middle of the street. He had been shot several times. He was rushed to Harborview Medical Center, where he later died of his injuries.

According to police, the shooter pulled up next to Noll in his car and for reasons that may be related to road rage, fired multiple rounds at Noll, striking him several times. The suspect then fled the scene in his car and remains at large.

Sunday afternoon, police released a brief surveillance video of the suspect's vehicle near the homicide scene. Watch that video here.

The suspect's vehicle is described as a silver BMW Z4 convertible. The car may have recent body damage, including a broken-out, passenger-side window.

Several witnesses describe the shooter as a well-dressed white or Asian male in his late 20s to 30s with dark, slicked-back hair.

Homicide and CSI detectives responded to the shooting scene and recovered numerous items of evidence.

Detectives are encouraging the suspect to turn himself in.

Meanwhile, a memorial is growing for Noll near his home, just blocks from where he was shot.

Friends describe Noll as a good-hearted outdoorsman who had been planning a kayaking trip in the coming days. They can imagine no motive for killing him.

"He had a heart of gold. He really cared about people," says another friend, Laural Waters. "It just feels senseless, given who he was."